1. Field of the Invention
The present invention relates to a lock mechanism and more particularly to a lock and a key for the same, which allows a user to change permutations of interior components of the lock freely.
2. Description of Related Art
There are several types of locks in the conventional technical field, wherein a pin tumbler lock is the most common type. The structure of the pin tumbler lock comprises a lock shell and a lock core unit mounted in the lock shell and including a core shell, a lock core and multiple lock bead units.
The core shell is tubular and has a receiving space formed in the core shell and multiple outer bead holes formed through one side of the core shell.
The lock core is cylindrical and has a key hole formed through a central portion of the lock core, and multiple inner bead holes formed through one side of the lock core and communicating with the key hole. The lock core is rotatably mounted in the core shell. The outer bead holes of the core shell correspond in position respectively to the inner bead holes.
Each lock bead unit includes an outer lock bead, an inner lock bead and an elastic element. The lock bead units are respectively mounted in the outer bead holes and the corresponding inner bead holes. The outer lock beads and the elastic elements are located in the outer bead holes. The elastic elements abut the outer lock beads and make inner ends of the outer lock beads protrude in the inner bead holes. The inner lock beads are located in the inner bead holes. Outer ends of the inner lock beads and the inner ends of the outer lock beads abut each other. Inner ends of the inner lock beads protrude into the key hole. Wherein, lengths of the outer lock bead and the inner lock bead of each lock bead unit correspond to lengths of key teeth of a key.
When the key is inserted into the key hole of the lock core, the key teeth respectively push the inner lock beads and make the inner lock beads and the outer lock beads move to a common boundary located between an inner wall of the core shell and an outer periphery of the lock core. The key can rotate the lock core toward a direction relative to the core shell to lock or unlock the lock apparatus.
However, in the conventional lock core, a specific length ratio of each lock core can only fit a permutation of the key teeth in a specific key. If a user has multiple keys for multiple lock apparatuses, the appearances of the keys are too similar and hard to be distinguished.
If a copy of key is lost, the user has to remake a new key from a master key, or to change the lock apparatus. If the master key is lost as well, the user has no any other choice and has to change the apparatus to prevent a housebreaker. It is very inconvenient and takes lots of money and time. Therefore, the pin tumbler lock in conventional technology still needs to be improved.